During the past year, the VRC's Vector Core created and tested new vaccine vectors expressing novel forms of envelope proteins. In addition, work continued to test different methods and routes of administration as well as prime/boost combinations to further optimize HIV vaccine strategies. DNA, VLP, nanoparticles and other vectors were tested. Several candidate vaccines that elicited promising immunogenicity data in preliminary studies are being tested further. Studies to develop and test bi-specific antibodies expressing 2 types of antibody with the goals of improving immunogenicity against HIV and targeting latent virus. In addition, studies continued to analyze ferritin nanoparticles expressing HIV envelope to induce CD4bs antibodies, identified by newly developed assays based on the resurfaced stabilized gp120 core with antigenic specificity for the initial site of CD4 attachment of gp120. Epitopes recognized by vectors expressing neutralizing antibodies were also analyzed and tested for their ability to induce similar types of antibodies, in vivo.